1. Field of the Invention
The present invention relates to computer systems which include at least one adapter card that is inserted into a connector present on the system board of the computer. More particularly, the present invention allows adapter cards having different voltages to be physically inserted into the same standard connector on the system board wherein the voltage level is detected. When the detected voltage is consistent with the programmed power supply voltage level of the computer system, the computer is enabled to begin its power on procedure.
2. Description of Related Art
As computer technology continually advances the voltage levels used to operate various types of microelectronic devices, i.e. transistors, is typically becoming lower. That is, existing, older devices may have been designed and manufactured to operate at 5.0 volts, while more recently developed devices may operate at 3.3 volts, or the like. Also, technical reasons may exist for having some devices operate at 3.3 volts and others at 5.0 volts. Thus, there are devices, such as I/O adapter cards, on the market that operate at different voltages. Further, these devices are often needed for various computing applications and must be accommodated by the available computer systems.
One specific example where this problem arises is in the area of I/O adapters connected to a computer system through a secondary bus. One popular type of secondary bus is the Peripheral Component Interconnect (PCI) Bus. The specification for this bus anticipates a need for both 3.3 volt and 5.0 volt adapters to address the various types of computer configurations that may be developed.
Computer system designers are often faced with the question of whether or not to support, for example, 3.3 volt PCI local bus I/O adapters in their systems. Generally, when a designer chooses to support 3.3 volt PCI adapters on the bus, then 5.0 volt adapters are not be supported. Therefore, the computer designers/manufacturers are in the position of deciding for the end user what types of I/O adapters can be used on the customer""s system. More particularly, if a computer manufacturer, such as IBM, Dell, Compaq, or the like, determines that the PCI bus will be compatible with 3.3 volt devices, then specific 3.3 volt compatible connectors will be attached to the system board of the computer. These 3.3 volt connectors will only physically accept 3.3 volt I/O adapters, i.e. 5.0 volt adapters cannot be inserted into 3.3 volt connectors. Similarly, 5.0 volt connectors cannot physically accept 3.3 volt adapters. Therefore, it can be seen that the end user is limited to using only those types of adapters which are compatible with the connectors physically mounted on the system board of the computer system.
The PCI Local Bus Specification defines two different connector types, 5.0 volt and 3.3 volt, while three different adapter types are defined, 5.0 volt, 3.3 volt (5.0 volt intolerant) and Universal (5.0 volt tolerant). A 5.0 volt PCI adapter card can only be inserted into a 5.0 volt PCI connector. Similarly, a 3.3 volt PCI adapter card can only be inserted into a 3.3 volt PCI connector. However, the Universal adapter card can be inserted in either. These restrictions are enforced by adapter and connector keying which is defined by the PCI Local Bus Specification.
Of course, it is possible to design a system with redundant PCI buses to accommodate cards of different voltages, i.e. both 3.3 volt connectors and 5.0 volt connectors, however, this type of design is costly and inefficient. Further, universal adapter cards exist which can be inserted into either a 3.3 volt or 5.0 volt connector, but the user is still limited. That is, the function desired by the user may not be implemented in an I/O adapter card available in a universal format.
Therefore, in order to maintain flexibility of the system design, it would be desirable if the ultimate system""s user could have the option of choosing whether to support 5.0 volt or 3.3 volt adapters, rather than being locked into one or the other. An example may be a system design which could be configured as a graphics workstation or as a low end server. The same computer system layout (e.g. processor, system bus, memory system, and the like), but different I/O adapters would be used to address the different applications. In this case, the graphics workstation may use 3.3 volt PCI adapter cards, while a low end server configuration could use 5.0 volt PCI adapter cards. In this case, it would be desirable to enable the system manufacturer to build one system, having a uniform type of connector which accepts both 3.3 and 5.0 volt cards, that would be capable of operating as either a graphics work station or a low end server.
Therefore, it can be seen that a need exists for a connector configuration that would accept either a 3.3 volt or 5.0 volt adapter card and determine whether the inserted adapters are compatible with one another and the programmed power supply voltage level of the computer system.
In contrast to the prior art, the present invention provides a connector capable of receiving differently configured I/O adapters. That is, by way of example, both a 3.3 volt adapter and 5.0 volt adapter can be inserted into a connector designed in accordance with the present invention.
Broadly, the present invention is a mechanism that allows the system user to determine the configuration of the I/O adapter cards to be used, independent of their voltage levels. More particularly, if the computer system power supply is programmed at a voltage level compatible with the desired adapter card, the present invention will allow the card to be inserted and used.
The present invention includes a connector that is physically capable of receiving any one of a variety of adapter cards, independent of the operating voltage level of the adapter cards. Further, the present invention comprehends a system design which will accept any PCI adapter type and then dynamically determine whether the configuration is valid, or not, prior to powering on the system. The present invention includes a customized PCI Local Bus connector type which will allow insertion of any PCI adapter type (e.g. 3.3 volt or 5.0 volt) and system logic capable of detecting the type of each installed PCI adapter and then allowing, or enabling the system to power on if the set of installed PCI adapters are compatible with each other and the programmed voltage level of the system power supply.
The present invention detects when a valid mix of adapter cards is inserted into the connectors on the system board of a computer. When adapter cards having different voltage ratings are inserted into the connector slots, power on operations are not allowed thereby preventing possible damage to the computer.
Therefore, in accordance with the previous summary, objects, features and advantages of the present invention will become apparent to one skilled in the art from the subsequent description and the appended claims taken in conjunction with the accompanying drawings.